Closer look and repair
You may notice from the outside or from the -14C in the label that this unit uses 14cm fan so it is not so terribly loud while only having efficiency of 80-86 %. However, as usual with low-pressure fans, about half of it is covered which surely helps keeping it silent with all those turbulences…fan is Yate Loon D14BH-12 (L-SSS), spinning at maximum 2800 RPM while achieving airflow of 140 CFM and noise of 48.5 dBA. Quite a turbine at full speed…
Soldering is OK for CWT. Seems that the output cables were the greatest difficulty. The unit uses ordinary two-transistor forward for the main supply. CM6800 is the combo driver for PFC and switching.
There is a strange thing about this one unit you may notice immediately upon opening. I said this is CWT unit, right? But it does not have green transformers! Well yes, they must have run out of green tape or I don’t know, but it is definitely from CWT. It is 100% same as the units X-bit labs reviewed. You may also notice the problem in there.
The stand-by supply ceased working properly as the output capacitor went bad. This is very common as the stand-by capacitors are most stressed as it runs 24/7. CWT opted for Samxon GF which is known bad series together with GK from Man Yue, other series are fine. I have replaced this cap together with all the rest (excl. primary capacitor). Interestingly though, different brands that used exactly this same platform opted for Chemi-Con caps. I think I have seen a Thermaltake with the same internals but NCC caps.
Unfortunately I forgot to take images after the recap and it is already a long time and the unit went away to the owner immediately. But fortunately it is not a big deal. For such power supplies I offer Chemi-Con KYA 3300/6.3 and Samxon RS 3300/16 caps, both in 10mm diameter! For this unit my very special Chemi-Con KZN 3300/16 D10×40 mm caps can also be used. Check my website for ATX PSU capacitors. I think I have measured the ripple just out of curiosity and it was quite nice for the time, lower rails about 30 mV and +12 V about 50 mV or so but I do not recall exactly.
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